Camera

ABSTRACT

A motor-driven camera of the prewind type arranged to perform a preliminary film winding action continuously from an automatic film loading onto a take-up spool before photographing and, thereafter, to rewind the film for every photographing shot includes an electric film counter arranged to count the number of frames of the film according to the transport of the film, a detecting device for detecting the movement of the film, and a detecting circuit which detects a cause for the immovable state of the film when the detecting device has detected the immovable state of the film. The detecting circuit is arranged to determine the preliminary film winding action to have been completed when a counted value of the electric film counter is greater than a predetermined value, or to determine the automatic film loading to have failed when the counted value is not greater than the predetermined value.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a motor-driven camera of the prewind type inwhich all frame portions of film are preliminarily wound onto a take-upspool and then the film is rewound for every photographing shot.

2. Description of the Related Art

The so-called automatic film loading by which blank film winding isperformed when a camera is loaded with a roll of film is intended toensure that the leader part of the film is reliably wound onto a spoolof the camera. However, the automatic film loading would fail if theposition of the film perforation does not coincide with the teeth of asprocket or if the leader part is not placed in a designated position.It has been practiced to wind several frame portion film by using amotor or the like and, at the same time, to detect a movement of thefilm. Then, if no movement is detected, the automatic film loading isconsidered to have failed.

However, in the case of a camera of the prewind type, the film loadingprocess for winding a part of the film onto the spool of the camera isimmediately followed by a continuous film winding process for windingthe film onto the spool to the end part of the film. In accordance withthe prewind system, therefore, it is impossible to find the entirelength of the film until completion of the prewinding action. Thelengths of the commercially available film products are limited toseveral different lengths. In some cases, however, the photographerwishes to cut the film to a desired length before use. The camera shouldbe arranged to be capable of handling such a film length. If theautomatic film loading is determined to have failed by detecting themovement of the film in accordance with the conventional method in sucha case, the automatic film loading would be determined to have failed,despite the performance of the loading, as the film comes to a stop alsoupon completion of the prewinding action.

For a camera having a prewind system, a method for making adiscrimination between the failure of the automatic film loading and thecompletion of the preliminary film winding has been disclosed in U.S.Pat. No. 4,460,256. This patent is for a motor-driven camera. The camerahas a prewind system and is arranged to have all the frame portions offilm first wound in response to closing of the back lid of the camera;and, after that, each of the frame portions of film is rewound back intoa film cartridge at the end of every photographing shot. Morespecifically, the camera is provided with a mechanical film countermechanism. The rotation of a sprocket is used as a drive source forrotating a disc-shaped counter plate. The film count value is indicatedby rotating this counter plate to a degree corresponding to one frame ata time. The film counter mechanism includes a detecting mechanism. Thedetecting mechanism consists of a cam and an operating piece and changesthe state of a switch in response to the movement of the operatingpiece. The cam is provided with a cut-out part which corresponds tothree frames. When a three-frame portion of the film is wound aftercommencement of the prewinding action, the operating piece swings byriding over the cam from the cut-out part to change the state of theswitch. In the case of this patent, the failure of the automatic filmloading is detected by operating the detecting mechanism in combinationwith an electric timer. More specifically, the camera is arranged todetermine that an automatic film loading action has failed if the stateof the switch does not change within a given period of time set at theelectric timer from the start of the prewinding action after the backlid of the camera is closed. Upon detection of the failure of the filmloading, the film driving motor is immediately brought to a stop.

SUMMARY OF THE INVENTION

One aspect of this invention resides in the provision of a camera whichis arranged such that: in a case where the film comes to a stop duringthe process of preliminary film winding, a film count value currentlyobtained at an electric film counter is compared with a predeterminedvalue. Then, a discrimination is made between the failure of theautomatic film loading and the completion of the prewinding actionaccording to the result of that comparison. The invented arrangement iscapable of accurately making a discrimination between the failure of theautomatic film loading and the completion of the prewinding actionprocess even in cases where the film is cut to a short length beforeuse. It is an advantage of the invention over the above-stated prewindtype camera of the prior art that the invented arrangement dispenseswith the use of the mechanical cam and the operating piece mentioned inthe foregoing description of the prewind type camera.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration showing in outline the arrangement of asingle-lens reflex camera arranged according to this invention as anembodiment thereof.

FIG. 2 is an oblique view showing the arrangement of each component partshown in FIG. 1.

FIGS. 3(a), 3(b) and 3(c) show the operation of the essential partsdisposed on the side of the spool of a film wind driving mechanism asviewed from below their positions shown in FIG. 2. Among these figures,FIG. 3(a) shows a state obtained at the beginning of the prewindingaction. FIG. 3(b) shows a state in which the leader part of the film hasbeen taken up onto the spool in the initial stage of the prewindingaction. FIG. 3(c) shows a state in which the back lid of the camera isin an open state.

FIG. 4 shows a detection gear of FIG. 2 as viewed from below. FIG. 5shows a detection substrate of FIG. 2 as viewed from above. FIG. 6 is atime chart showing the timing of signals obtained from the terminalsprovided on the detection substrate of FIG. 5.

FIGS. 7(a), 7(b) and 7(c) show the operation of a film rewind drivingmechanism and a mirror box driving mechanism as viewed from one side.Among these figures, FIG. 7(a) shows an initial state or in a stateobtained at the time of the prewinding action. FIG. 7(b) shows amirror-up state which a mirror has been raised. FIG. 7(c) shows amirror-down state in which the mirror has been lowered after actuationof the mirror box driving mechanism.

FIGS. 8(a) and 8(b) show the operation of a brush on a signal substrate,FIG. 8(a) showing a state in which the shutter charge has been completed(mirror-down state), and FIG. 8(b) showing a state in which the mirrorhas been raised (the shutter charge being cancelled).

FIGS. 9(a), 9(b), 9(c) and 9(d) show the operation of the film rewinddriving mechanism as viewed from above. Among these figures, FIG. 9(a)shows an initial state or a state obtained at the time of the prewindingaction. FIG. 9(b) shows a state in which the mirror box drivingmechanism is operated by the reverse rotation of a motor. FIG. 9(c)shows a state in which the film rewind driving mechanism is operated bythe normal rotation of the motor. FIG. 9(d) shows a state in which theback lid of the camera has been opened.

FIGS. 10(a), 10(b), 10(c) and 10(d) show the operation of the essentialparts of the film wind driving mechanism disposed on the side of themotor as viewed from below. Among these figures, FIG. 10(a) shows aninitial state, or in a state obtained at the time of the prewindingaction. FIG. 10(b) shows a state in which the mirror box drivingmechanism is operated by the reverse rotation of the motor. FIG. 10(c)shows a state in which the film rewind driving mechanism is operated bythe normal rotation of the motor. FIG. 10(d) shows a state in which theback lid has been opened.

FIG. 11 is a circuit diagram showing essential parts participating in acontrol over the camera. FIGS. 12(a), 12(b), 13(a) and 13(b) are flowcharts.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The following describes an embodiment of this invention with referenceto the accompanying drawings. In this case, the invention is applied toa single-lens reflex camera. FIG. 1 shows in outline the arrangement ofthe single-lens reflex camera. A photo-taking lens 1 is detachablymounted on a camera body 10. The illustration includes a shutter releasebutton 2, a film rewinding button 3 which is arranged to cause all theframe portions of film to be forcedly rewound, and a battery 4 which isdisposed in the bottom part of the camera body 10. The camera body 10 isprovided with a member which serves as a battery lid and which isreadily removable when taking out the battery from a battery holdingchamber for replacing it with a new battery. A motor M1 is arranged toserve as a drive source not only for film winding and rewinding systemsbut also for charging a front panel system and for driving a mirror. Theillustration further shows a film wind driving mechanism 5, a filmrewind driving mechanism 6, a mirror box driving mechanism 7, and a filmcounter mechanism 8.

The details of the above-stated arrangement are as described below withreference to FIG. 2 and other figures showing the details of therespective components of the invention.

First, the motor M1 has two output shafts including upper and loweroutput shafts. The two output shafts are arranged to rotate insynchronism with each other.

Next, the film wind driving mechanism 5 is arranged as follows:Referring to FIG. 2, a first pinion 20 is secured to the lower outputshaft of the motor M1. A transmission gear 22 meshes with the firstpinion 20. The transmission gear 22 is connected to a sun gear 26 via aconnection shaft 24. Gears 26 and 28 and a planetary lever 30 arearranged to jointly form a planetary clutch mechanism. The planet gear28 meshes with the sun gear 26 and is arranged to be revolved by theplanetary lever 30 which is friction-coupled with the sun gear 26. Atransmission gear 32 is disposed at a position where it meshes or doesnot mesh with the planet gear 28 according to the revolution of theplanet gear 28. When the sun gear 26 rotates counterclockwise to revolvethe planet gear 28, the transmission gear 32 meshes with the planet gear28 to transmit the rotation of the motor M1. When the sun gear 26 iscaused to rotate clockwise by the reverse rotation of the motor M1, theplanet gear 28 is disengaged from the transmission gear 32. Transmissiongears 34 and 36 are arranged to transmit the rotation of thetransmission gear 32. The gear 36 is a double gear and meshes withanother sun gear 38.

Gears 38 and 40 and a first planetary lever 42 form a first planetaryclutch mechanism. The small gear part of the sun gear 38 which is adouble gear meshes with a first planet gear 40 which is revolvable bythe first planetary lever 42 (friction-coupled with the small gear partof the sun gear 38). Gears 38 and 46 and a second planetary lever 44form a second planetary clutch mechanism. The small gear part of the sungear 38 further meshes with the second planet gear 46 which isrevolvable by the second planetary lever 44 (friction-coupled with thesmall gear part of the sun gear 38). A spool driving transmission gear48 is disposed in a position where it meshes or does not mesh with thefirst planet gear 40 according to the revolution of the first planetgear 40. When the first planet gear 40 is caused to revolve by theclockwise rotation of the sun gear 38, the transmission gear 48 mesheswith the first planet gear 40 to transmit the rotation of the motor M1.When the motor M1 rotates in a reverse direction, the transmission ofrotation of the motor 1 is cut off by the above-stated planetary clutchmechanism (26, 28, 30) which is disposed on the upstream side of thefilm wind driving mechanism 5. In that event, therefore, the firstplanetary lever 42 does not turn counterclockwise.

A spool gear 50 is arranged to drive a spool 52 for taking up a film.The spool gear 50 constantly meshes with the transmission gear 48 and issecured to the above-stated spool 52 although the spool gear 50 isillustrated in FIG. 2 as being located away from the spool 52. On thecircumferential surface of the spool 52 are formed spool claws 52a whichare arranged to engage a perforation provided in a roll of film F.

A transmission gear 54 is a double gear arranged to drive a sprocket.The large gear part of the gear 54 is disposed in a position where itmeshes or does not mesh with the second planet gear 46 according to therevolution of the second planet gear 46. When the sun gear 38 rotatesclockwise, the gear 54 meshes with the second planet gear 46 due to therevolution thereof to transmit the rotation of the motor M1. A sprocketgear 56 is arranged to drive a driving sprocket 58. The sprocket gear 56constantly meshes with the small gear part of the transmission gear 54and is in a rotatory association with the driving sprocket 58. Althougha mechanism for associating the sprocket gear 56 with the drivingsprocket 58 is omitted in FIG. 2 for the sake of simplification ofillustration, they are in actuality rotatively associated with eachother. The driving sprocket 58 is provided with teeth 58a which arearranged to be capable of meshing with the perforation of the film F.

The spool 52 is arranged to be greater in a circumferential speed ratiothan the driving sprocket 58.

In the neighborhood of the fore end part of the second planetary lever44 of the second planetary clutch mechanism, there is provided astructural arrangement for disengaging the second planet gear 46 fromthe transmission gear 54 and for keeping them in the disengaged state.The details of this structural arrangement are as described below withreference to FIGS. 3(a), 3(b) and 3(c) which are bottom plan viewsshowing the essential parts of the arrangement:

The second planetary lever 44 is provided with a notch 44a, a projection44b and a hill-shaped click part 44c which are formed near to the foreend of the lever 44. A reset lever 60 is arranged to be swingable aroundits rotation center 60a. The lever 60 has a restricting part 60b whichis in a bent shape, a first projection 60c, and a second projection 60dwhich protrudes toward the back lid of the camera. A holding lever 62 isconcentrically carried by the rotation center 60a of the reset lever 60and is arranged to be swingable to a small degree of angle which isrestricted by the above-stated restricting part 60b. This holding lever62 is provided with a pin 62a which is disposed in a positioncorresponding to the notch 44a of the second planetary lever 44 and aclick projection 62b which is disposed in a position corresponding tothe above-stated hill-shaped click part 44c. A holding spring 64 issecured to the above-stated reset lever 60 and is arranged toelastically push the holding lever 62 to cause the click projection 62bto abut on the click part 44c. A reset spring 66 is elastically pushingthe reset lever 60 counterclockwise as viewed on FIGS. 3(a), 3(b) and3(c). A reference numeral 70 denotes the back lid of the camera which ispivotally carried by a shaft 70a and is arranged to be opened and closedas desired. With the back lid 70 in a closed state, a pushing part 70bof the back lid 70 pushes the above stated second projection 60d of thereset lever 60 to cause the reset lever 60 to be pushed into itsposition as shown in FIGS. 2, 3(a) and 3(b) and keeps it there againstthe force of the above-stated reset spring 66.

Under the condition in the beginning of a film winding action, as shownin FIG. 3(a), therefore, the second planetary lever 44 causes the planetgear 44 to mesh with the transmission gear 54. When a portion of theleader part of the film is taken up onto the spool 52, the drivingsprocket 58 comes to be driven by the movement of the film F, and thenthe rotational frequency of the second planet gear 46 no longercoincides with that of the transmission gear 46. In the initial stage offilm winding, therefore, a rotating force is exerted as a repulsingforce on the second planetary lever 44 to be turned clockwise in FIG.3(a). This force causes the lever 44 to turn clockwise. The turningmotion causes the click projection 62b to ride over the click part 44c,as shown in FIG. 3(b). This disengages the second planet gear 46 fromthe transmission gear 54. Under this condition, the holding lever 62 ispushed by the holding spring 64 toward the second planetary lever 44.The holding lever 62 then has the click projection 62b push the clickpart 44c on a part extending from its top to its slanting side face andis thus kept in that position. This state which is shown in FIG. 3(b) iskept until the back lid 70 is opened next time. In this state, it isonly the spool 52 that exerts a driving force for winding the film F(spool drive).

When the back lid 70 is opened as shown in FIG. 3(c), the reset lever 60swings counterclockwise by the pushing force of the reset spring 66.Therefore, the holding lever 62 likewise swings counterclockwise. Thistime, the pin 62a pushes the projection 44b of the second planetarylever 44 to swing the lever 44 counterclockwise. This brings the secondplanet gear 46 back to its initial position where it is allowed to meshwith the transmission gear 54.

The details of the film counter mechanism 8 and the film transportdetecting mechanism are arranged as follows. Referring again to FIG. 2,a reference numeral 80 denotes a follower sprocket. The followersprocket 80 is not associated with the above-stated driving sprocket 58and is arranged to rotate only by following the movement of the film F.A transmission gear 82 is secured to the follower gear 80. A detectiongear 84 meshes with the transmission gear 82 and is arranged to make oneturn while one frame portion of film (normally having eight perforationholes) is transported. A counter advancing shaft 86 has a cutout tooth86a formed in the upper end part thereof and is arranged to rotate inassociation with the detection gear 84. Referring to FIG. 4, theassociated rotation of the counter advancing shift 86 and the detectiongear 84 is caused by the engagement of external teeth 86b formed at thelower end of the shaft 86 with inner teeth 84a formed in the middle holeof the detection gear 84. The external teeth 86b and the inner teeth 84aare arranged to mesh with each other loosely in the radial direction.Therefore, the counter advancing shaft 86 is movable to a slight extentin the radial direction of the detection gear 84. A counter gear 88 isrotatably carried by its center shaft 88a and is being urged to rotateclockwise by a spring which is not shown. The circumferential face ofthe counter gear 88 has a toothed part 88b which is arranged to rotateone pitch degree when the counter advancing shaft 86 makes one turn. Onthe upper surface of the counter gear 88 is provided a film frame numberindicator 88c which has frame numerals spaced to a degree coincidingwith the pitch of the toothed part 88b. A counter reset lever 90 isswingably carried by its center shaft 90a and is provided with aprotruding pin 90b which is arranged to be pushed by the pushing part70c of the back lid 70 when the back lid 70 is closed and a pushing part90c which is arranged to push the counter advancing shaft 86 when thecounter reset lever 90 swings counterclockwise. A spring 92 has itsmiddle part carried by a pin 90d which is provided on the counter resetlever 90. One end of the spring 92 abuts on a fixed pin 92a while theother end abuts on the counter advancing shaft 86. While the back lid 70is closed, as shown in FIG. 2, the spring 92 elastically pushes thecounter advancing shaft 86 toward the center of the counter gear 88 toensure that the toothed part 88b of the counter gear 88 is in contactwith the upper end part of the counter advancing shaft 86 (having thecutout tooth 86a). This ensures an adequate advancing action of the gear88 and prevents it from coming back to its initial position. When theback lid 70 is opened, the counter reset lever 90 is released from itsstate of being held in position. This allows the counter reset lever 90to swing counterclockwise by the urging force of the spring 92. Thepushing part 90c of the lever 90 then pushes the counter advancing shaft86 in the direction opposite to the counter gear 88. This leaves thecounter gear 88 in a freely movable state. The force of a spring whichis not shown then causes the counter gear 88 to rotate clockwise back toits initial position where a mark "E" appears in an indication windowwhich is provided for showing the film frame number. When the back lid70 is closed after this, the upper end part of the counter advancingshaft 86 again enters the toothed part 88b of the counter gear 88. Thisenables the cutout tooth 86a to intermittently advancing the gear 88 byone tooth in the direction of incrementing the frame number.

A detection substrate 94 is disposed beneath the detection gear 84. Thedetection gear 84 and the detection substrate 94 jointly form amechanism for detecting the transport amount of the film F. The detailsof the film transport amount detecting mechanism are shown in FIGS. 4and 5.

FIG. 4 shows the detection gear 84 as viewed from the reverse sidethereof. A sliding brush 85 is attached to the reverse side of the gear84. FIG. 5 shows the detection substrate 94 as viewed from the obverseside thereof. A comb-shaped pattern 94a, a duty control pattern 94b, abrake control pattern 94c and a ground pattern 94d are formed within asliding area of the above-stated brush 85 which is caused by therotation of the detection gear 84. These pattern 94a to 94d areconnected to terminals 95 to 97, respectively. Further, two-dot chainlines 98 in FIG. 5 indicate the sliding area of the sliding brush 85which in actuality has the sliding width of the brush 85. A ground levelsignal is supplied to the terminal 96 by a circuit which will bedescribed later. This makes it possible to detect a movement signal (apulse signal) by the terminal 95 during a film frame advancing process.A duty control range which is obtained near the end of the film frameadvancing process can be detected by the terminal 97. Further, a brakecontrol range which is obtained at the end of the film frame advancingprocess can be detected by the terminals 95 and 97. More specifically,referring to FIG. 6 which is a time chart showing the film rewindingprocess, the film advancing amount detection is carried out as follows.With the ground level signal supplied to the terminal 96, a pulse signalis obtained at the terminal 95 as the sliding brush 85 is first broughtinto sliding contact with the comb-shaped pattern 94a and the groundpattern 94d by a rewinding action on one frame portion of the film. Thegenerating interval of the pulse signal is in synchronism with the filmtransport speed. Therefore, it can be detected that the film F is beingappositely transported (either for winding or rewinding) if thegenerating interval of the pulse signal is shorter than a predeterminedperiod of time. If the generating interval is longer than thepredetermined period of time, it indicates either that the voltage ofthe battery has dropped or that film winding or rewinding has beencompleted for all the frame portions to have either a so-called filmstretching state or a state of having the film completely taken up intothe film cartridge.

Next, a ground level signal is obtained at the terminal 97 when thesliding brush 85 slides on the duty control pattern 94b and the groundpattern 94d. The start end 94b-1 of the duty control pattern 94b is setin such a way as to have the timing of the ground level signal insynchronism with a time point near the end of rewinding of one frameportion of the film F (frame advance). Then, in order to reduce thespeed of the motor M1 after this point, a speed reducing control isaccomplished by changing the power supply from a full power supply modeover to a duty pulse power supply mode.

Further, when the sliding brush 85 comes into sliding contact with allof the duty control pattern 94b, the brake control pattern 94c and theground pattern 94d, a ground level signal is obtained at both theterminals 95 and 97. The start end 94c-1 of the brake control pattern94c is set in such a way as to have the timing of this ground levelsignal in synchronism with a point which is set immediately before theend of rewinding of one frame portion of the film F (in anticipation ofan overrun extent). In order to stop the motor M1 rapidly after thispoint, a stopping control is accomplished by switching over to ashort-circuit mode.

The details of the film rewind driving mechanism 6 and those of themirror box driving mechanism 7 are as follows. Again referring to FIG.2, a second pinion 100 is secured to the upper output shaft of the motorM1. A transmission gear 102 which is in the form of a double gear mesheswith the second pinion 100. Parts 104, 106 and 108 form a planetaryclutch mechanism. A sun gear 104 which is in the form of a double gearmeshes with the transmission gear 102. A planet gear 106 which is in theform of a double gear meshes with the sun gear 104 and is arranged to berevolvable by a planetary lever 108 which is friction-coupled with thesun gear 104. A rewind gear 110 is disposed in a position in which itmeshes with the small gear part of the planet gear 106 according to therevolution of the planet gear 106 in a first direction (the clockwiserotation of the sun gear 104 caused by the clockwise rotation of themotor M1). A rewind fork 112 is arranged to mesh with the shaft of afilm cartridge in a known manner. The fork 112 is stronglyfriction-coupled with the rewind gear 110.

A transmission gear 120 is included in the mirror and shutter-chargingdrive and transmission system and is arranged in a position in which itmeshes with the large gear part of the planet gear 106 according to therevolution of the planet gear 106 in a second direction (thecounterclockwise rotation of the sun gear 104 caused by thecounterclockwise rotation of the motor M1). A transmission shaft 122 hasone end thereof secured to the transmission gear 120 and the other endto a worm gear 124. A mirror driving gear 126 is arranged to mesh withthe worm gear 124 and to rotate clockwise when the motor M1 rotatescounterclockwise. The gear 126 has a mirror driving cam 128 formed onits obverse side in one unified body therewith. To the reverse side ofthe mirror driving gear 126 is secured a position detecting brush 130which will be described later herein. A mirror driving lever 132consists of two lever bodies and serves as a cam follower for theabove-stated mirror driving cam 128. More specifically, the mirrordriving lever 132 is arranged to be driven to rotate counterclockwise bythe mirror driving cam 128 when one end part 132a of the lever 132 comesinto sliding contact with an uprising cam face 128a of the cam 128 (seeFIGS. 7(a), 7(b) and 7(c)); to keep on rotating counterclockwise whenthe end part 132a is in sliding contact with a level cam face 128b (seeFIGS. 7(a), 7(b) and 7(c)); and to be allowed to resume its clockwiserotation when the end part 132a comes either into sliding contact with adescending cam face 128c or to a position corresponding to the face128c. The mirror driving lever 132 drives a mirror by the other end part132b swinging under the control of the rotating position of each camface of the mirror driving cam 128. A reference numeral 134 denotes amovable mirror which is turnably carried to have two positions. One is afinder sighting position (or a mirror-down state) in which the movablemirror 134 reflects an object light coming through the photo-taking lens1 to a view finder optical system (not shown), as shown in FIGS. 2 and7(a). The other is an exposure-allowing retracted position (or amirror-up state) in which the movable mirror 134 is turned to allow theobject light to come to the film, as shown in FIG. 7(b). A carryingframe 136 has the movable mirror 134 secured thereto and is providedwith rotating shafts 136a which are formed at two side end parts of thecarrying frame 136. The carrying frame 136 is thus movably carriedwithin a mirror box by the shafts 136a. A mirror pin 138 is formed onone side of the carrying frame 136 and abuts on the other end part 132bof the above-stated mirror driving lever 132. Further, the carryingframe 136 is constantly receiving the urging force of a spring 140 whichis exerted counterclockwise (in the direction of the mirror-down state).Therefore, when one end part 132a of the mirror driving lever 132 comesinto sliding contact with the uprising cam face 128a of the mirrordriving cam 128, the mirror driving lever 132 receives acounterclockwise turning force. The lever 132 then maintains itscounterclockwise turning state when it is in sliding contact with thelevel cam face 128b of the cam 128, and is then allowed to resume itsclockwise turning motion by coming into sliding contact with thedescending cam face 128c. The other end part 132b of the mirror drivinglever 132 acts, under the control of the turning positions of the mirrordriving cam 128, to raise the movable mirror 134 by pushing the mirrorpin 138, to retain the mirror 134 in the mirror-up state by continuouslypushing the pin 138, and to allow the mirror 134 to be lowered byreleasing the mirror pin 138 from the pushing action.

A shutter charge gear 142 is arranged to rotate counterclockwise bymeshing with the above-stated mirror driving gear 126. A shutter chargecam 144 is formed on the obverse side of the gear 142 in one body withthe gear 142. The shutter charge gear 142 and the mirror driving gear126 are arranged to be in the transmission ratio of 1:1 to each other(reduction ratio: 1.0). The shutter charge cam 144 is provided with anuprising cam face 144a (see FIGS. 7(a), 7(b) and 7(c)) for driving ashutter charge lever 146 counterclockwise, a level cam face 144b forkeeping the lever 146 in the turning position or a charging state (seeFIGS. 7(a), 7(b) and 7(c)), and a descending cam face 144c (see FIGS.7(a), 7(b) and 7(c)) for causing the lever 146 to turn clockwise.

The shutter charge lever 146 is about in an L shape. A center shaft 146arotatably carries the shutter charge lever 146 to allow the lever 146 tofollow the movement of the above-stated shutter charge cam 144. Morespecifically, the shutter charge lever 146 is provided with a roller146b which is carried by one end part of the lever 146. The lever 146 isarranged to turn counterclockwise while the roller 146b is abutting onan uprising cam face 144a of the shutter charge cam 144, to keep onturning counterclockwise while the roller 146b is abutting on a levelcam face 144b, and to be allowed to turn clockwise when the roller 146breaches a descending cam face 144c of the cam 144. Another roller 146cwhich is carried by the working end of the shutter charge lever 146 isarranged to push one end of a charging lever disposed within a shutterunit under the control of the cam faces of the shutter charge cam 144.The charging lever is pushed to perform a shutter charging action and tocontinue the charging action. Under this condition, both the leading andtrailing groups of shutter blades can be mechanically kept in theirpositions in which they are ready for traveling. The details of theshutter unit have already been disclosed in U.S. patent application Ser.No. 137,888 filed on Dec. 24, 1987 and, therefore, are omitted from thedescription given herein. The ready-for-travel states of the leading andtrailing groups of shutter blades are canceled when the charging leveris released from the pushing action. After that, the shutter blades canbe allowed to travel as desired under power supply control overelectromagnets provided for shutter control.

As will be readily understood by comparing FIGS. 7(b) and 7(c), themirror-up driving phase of the mirror driving lever 132 which is broughtabout by the mirror driving cam 128 and the charge driving phase of theshutter charge lever 146 which is brought about by the shutter chargecam 144 are arranged to completely deviate from each other. In otherwords, when the shutter charge lever 146 is driven for charging by theshutter charge cam 144, the mirror driving cam 128 does not push themirror driving lever 132 and the movable mirror 134 is left in themirror-down state, as shown in FIG. 7(c). When the movable mirror 134 israised with the mirror driving lever 132 pushed by the mirror drivingcam 128, the shutter charge lever 146 is released from the shuttercharging state by the shutter charge cam 144, as shown in FIG. 7(b).This cancels the mechanical holding (clamping) action on theready-for-travel states of the leading and trailing groups of shutterblades.

Next, the details of a mechanism which is included in the embodiment forelectrically detecting shutter charging and mirror-up driving phases areas described below with reference to FIGS. 8(a) and 8(b).

A signal substrate 160 which is omitted from FIG. 2 for the sake ofsimplification of illustration is disposed on the reverse side of themirror driving gear 126 in a position within the slidable range of abrush 130. On the signal substrate 160 are formed by vapor deposition orthe like three position detecting patterns including a ground pattern161, an action end detection pattern 162 and an overrun detectionpattern 163. Referring to FIGS. 8(a) and 8(b), the relation of the brush130 to these patterns 161, 162 and 163 is as described below:

The sliding part 130a of the brush 130 is divided into a comb shape forthe purpose of increasing the safety of contact with the patterns 161 to163 disposed on the signal substrate 160. The actual sliding positionover this sliding part 130a, i.e. contact points, is on a line 130bwhich is located inwardly away from the tip of the brush 130.

FIG. 8(a) which corresponds to FIG. 7(c) shows the detecting mechanismin a phase in which completion of the shutter charging action isdetected. The brush 130 turns clockwise as indicated by an arrowaccording to the clockwise rotation of the mirror driving gear 126. Inthe state shown in FIG. 8(a), the sliding part 130a of the brush 130 isin contact both with the ground pattern 161 and the action end detectionpattern 162. The potential of a connector part (land part) 162a of thepattern 162 then changes to a ground level to permit detection ofcompletion of the shutter charging action. Further details of thisdetecting action are as follows. A ground level signal is supplied to aconnector part (land part) 161a of the ground pattern 161. The output ofthe connector part 162a of the action end detection pattern 162 issupplied to a control circuit of the camera. When the brush 130 islocated in a position preceding the position shown in FIG. 8(a) (i.e. ina position preceding in the counterclockwise direction), the slidingpart 130a of the brush 130 is in contact solely with the ground pattern161 and the potential of the action end detection pattern 162 has notyet changed to the ground level. Then, the mirror driving gear 126 isfurther rotated clockwise to cause the clockwise turn of the brush 130.When reaching the position shown in FIG. 8(a), the brush 130 which ismade of a conductive material comes into contact with the action enddetection pattern 162, so that the potential of the pattern 162 ischanged through the brush 130 to the ground level to allow the controlcircuit of the camera to detect completion of the shutter chargingaction. The control circuit then performs a control action to cause thedriving rotation of the motor M1 to stop.

FIG. 8(b) which corresponds to FIG. 7(b) shows the detecting mechanismin another phase in which completion of the mirror-up action isdetected. The brush 130 turns clockwise as indicated by an arrow fromthe position of FIG. 8(a) accordingly as the mirror driving gear 126rotates clockwise. When the brush 130 thus reaches the position shown inFIG. 8(b), the sliding part 130a changes from a state in which it is incontact with both the ground pattern 161 and the action end detectionpattern 162 to a state in which it is not in contact with the detectionpattern 162. The connector part (land part) 162a of the detectionpattern 162 then has its potential change from the ground level back toits initial level, which is normally a high level. This change permitsdetection of completion of the mirror-up action. Further details of thisdetection are as follows: When the brush 130 is located in a positionpreceding the position of FIG. 8(b) as viewed in the counterclockwisedirection, the sliding part 130a of the brush 130 is in contact withboth the ground pattern 161 and the action end detection pattern 162,and the connector part 162a of the action end detection pattern 162 isthen still supplying the control circuit of the camera with the groundlevel signal. Then, the mirror driving gear 126 is further rotatedclockwise under this condition to cause the brush 130 to turn alsoclockwise. When the brush 130 reaches the position of FIG. 8(b), thebrush 130 changes to a state in which it is not in contact with theaction end detection pattern 162. Then, the potential of the action enddetection pattern 162 is changed from the ground level to its initiallevel to allow the camera control circuit to detect completion of themirror-up action. The control circuit then controls and brings arotatory driving action on the motor M1 to a stop.

Referring now mainly to FIGS. 2, 7(a), 7(b) and 7(c) the details of thechange-over arrangement of the film winding and rewinding mechanism, themirror driving mechanism and the shutter charging mechanism are asfollows. For the sake of simplification of illustration, a change-overlever 170 is illustrated by a two-dot chain line. This change-over lever170 is pivotally carried by a center shaft 170a to be swingable aroundthe shaft 170a and is provided with a first restrictive projection 170bwhich is formed at the upper end part of the lever 170 and secondrestrictive projection 170c which is formed at the lower end part of thelever 170. A spring 172 is arranged to urge the changeover lever 170 toturn clockwise. A clamp lever 174 is swingably disposed on thechange-over lever 170 and is provided with a latch claw 174a which isformed at one end of the lever 174 and a projection 174b which is formedat the other end of the lever 174. A spring 176 is arranged to urge theclamp lever 174 to turn counterclockwise. The spring 176 has one endthereof attached to the change-over lever 170 and the other end to theclamp lever 174. The latch claw 174a engages a clamping projection 170dformed on the change-over lever 170 in its initial state, as shown inFIGS. 2 and 7(a), and is kept in that engaging position by the urgingforce of the spring 176. Meanwhile, the projection 174b of the clamplever 174 is located within the moving locus of a pushing projection132c formed on the mirror driving lever 132. When the mirror drivinglever 132 turns counterclockwise to raise the mirror 134, as shown inFIG. 7(b), the pushing projection 132c pushes the projection 174b toturn the clamp lever 174 clockwise in such a way as to relieve the clamplever 174 from its clamping state. Under this condition, the change-overlever 170 is allowed to turn clockwise to some degree to come to theposition of FIG. 7(b).

A reset lever 178 is swingably carried (see FIGS. 2 and 9(a) to 9(d))and has a projection 178a formed at one end thereof and a pushingprojection 178b at the other end. A strong spring 180 urges the resetlever 178 to turn counterclockwise and has a stronger spring force thanthe spring 172 which is exerting an urging force on the change-overlever 170. Therefore, when the black lid 70 is closed, the projection70d of the back lid 70 pushes the projection 178a to keep the resetlever 178 in the state of FIGS. 2 and 9(a). This allows the change-overlever 170 to turn clockwise. However, when the back lid 70 is opened torelieve the reset lever 178 from the pushed state as shown in FIG. 9(d),the reset lever 178 turns counterclockwise to cause the change-overlever 170 which has turned clockwise by the spring 172 to turncounterclockwise against the force of the spring 172 until the lever 170comes back to its initial position shown in FIG. 2. In returning thechange-over lever 170 back to the initial position, the clamp lever 174has its pin 174c guided by a guide projection 170e which has a cam faceand which is formed on the reverse side of the change-over lever 170.The lever 174 is thus guided until the latch claw 174a comes to engagethe clamping projection 170d. After that, the change-over lever 170 iskept in its initial position even when the rest lever 178 is caused toturn again with the back lid 70 closed.

The function of the change-over lever 170 is as described below withreference to the drawings including FIGS. 9(a) to 9(d) and 10(a) to10(d).

While the change-over lever 170 is in the initial position as shown inFIGS. 2 and 7(a), the first restrictive projection 170b which isdisposed at the upper end of the lever 170 is located in between theplanet gear 106 and the rewinding gear 110, as shown in FIG. 9(a).Meanwhile, the second restrictive projection 170c which is disposed atthe lower end of the lever 170 is located away from between the planetgear 28 and the transmission gear 32, as shown in FIG. 10(a). Under thiscondition, therefore, a film winding action can be performed by theclockwise rotation of the motor M1 as the planet gear 28 is allowed tobe revolved in a direction in which it meshes with the transmission gear32. However, no film rewinding action is allowed to be performed by theclockwise rotation of the motor M1 as the planet gear 106 is inhibitedby the first restrictive projection 170b from revolving in a directionin which it meshes with the rewinding gear 110, as the center shaft 106aof the planet gear 106 comes to abut on the first restrictive projection170b during its revolving movement. Meanwhile, the mirror driving andthe shutter charging actions can be performed by the counterclockwiserotation of the motor M1 as the planet gear 106 is allowed to berevolved in a direction in which it meshes with the transmission gear120 without being affected by the above-stated first restrictiveprojection 170b.

When the change-over lever 170 turns clockwise as shown in FIGS. 7(b)and 7(c), the first restrictive projection 170b of the upper end movesaway from its position between the planet gear 106 and the rewindinggear 110, as shown in FIGS. 9(b) and 9(c). The second restrictiveprojection 170c of the lower end then enters between the planet gear 28and the transmission gear 32, as shown in FIGS. 10(b) and 10(c). Underthis condition, therefore, the planet gear 106 is allowed to be revolvedin a direction in which it meshes with the rewinding gear 110 by theclockwise rotation of the motor M1, so that the film rewinding actioncan be accomplished. However, the planet gear 28 is inhibited by thesecond restrictive projection 170c from revolving in a direction inwhich it meshes with the transmission gear 32, as the center shaft 28aof the planet gear 28 comes to abut on the second restrictive projection170c during the revolving movement, so that the film winding actioncannot be accomplished under this condition. Further, even under thiscondition, the planet gear 106 and the transmission gear 120 can berevolved to mesh with each other by the counterclockwise rotation of themotor M1.

The camera control circuit will not be described with reference to FIG.11. The illustration includes a microcomputer CPU; and a battery BAT. Apower supply switch SW1 is turned on in response to the first stroke ofa pushing operation on a shutter release button 2 (see FIG. 1). With thepower supply switch SW1 turned on, a transistor TR_(BAT) is turned onvia a diode D_(SW1) and a resistor R2. With the transistor TR_(BAT) thusturned on, a power supply to each applicable circuit begins. The outputof the power supply switch SW1 is also supplied to an input port SW1 ofthe microcomputer CPU. When a back lid switch SWBP which will bedescribed later is turned on (closed), a one-shot circuit OS comes toact for a given period of time. The transistor TR_(BAT) is arranged tobe turned on also by this action of the one-shot circuit OS via a diodeD_(OS) and the resistor R2. The arrangement for bringing the transistorTR_(BAT) into an on-state by closing of the back lid 70 is provided forthe purpose of effecting a power supply to the microcomputer CPU toenable the microcomputer CPU to perform the control over the so-calledprewinding system including the film loading action and the operation ofpreliminarily winding all the frame portions of film. Further, if themicrocomputer CPU is in an operative state having its output port V_(ON)at a high level, the transistor TR_(BAT) is kept in its on-state via aninverter I1 and the resistor R2.

In FIG. 11, a reference symbol REG denotes a regulator. The regulatorREG is arranged to supply a stable, constant voltage Vcc to each ofcircuits connected to the collector output terminal of the transistorTR_(BAT). (In the case of FIG. 11, the constant voltage Vcc is suppliedto the input port Vcc of the microcomputer CPU and to an analog circuitMET which is arranged to perform a photometric computing operation.) Areference symbol MET denotes the analog circuit which performsphotometric computation. The circuit MET is arranged to perform acomputing operation "Bv-Av" on an object luminance information Bv whichis obtained by a photometric sensor SPC and a resistance R_(AV) whichcorresponds to a preset aperture value information Av and to supply itsoutput BV1_(OUT) to an input port AD_(IN1) of the microcomputer CPU. Theinput port AD_(IN1) is arranged to receive an AD conversion input. Aresistor R_(ISO) has a resistance value corresponding to filmsensitivity information Sv and is arranged to supply the information toan input port AD_(IN2) of the microcomputer CPU. A reference symbolV.sub. BAT denotes the voltage of the battery BAT. The battery voltageV_(BAT) is supplied to the input port AD_(IN3) of the microcomputer CPUand a transistor bridge circuit MD which will be described later.

A film loading detection switch SWPT_(IN) is composed of, for example, aleaf spring disposed within a film cartridge chamber of the camera. Whenthe film cartridge is placed in the cartridge chamber, the leaf springis pushed by the cartridge to turn on the switch SWPT_(IN). The outputof the switch SWPT_(IN) is supplied to an input port PT_(IN) of themicrocomputer CPU.

A back lid switch SWBP is turned on when the back lid 70 (see FIG. 2)closes and is turned off when the back lid 70 opens. The output of theback lid switch SWBP is supplied to an input port BP of themicrocomputer CPU and to the one-shot circuit OS. A switch SW_(CMSP) isarranged to operate according to the sliding movement of the brush 130over the action end detection pattern 162 on the signal substrate 160(see FIG. 8). A point of time at which the output level of this switchSW_(CMSP) changes from a low level to a high level represents amirror-up (shutter-charge release) phase. Another point of time at whichthe output level of the switch SW_(CMSP) changes from a high level to alow level represents a mirror-down (shutter charge) phase. The output ofthe switch SW_(CMSP) is supplied to an input port CMSP of themicrocomputer CPU.

Reference symbols SW_(FLSP) and SW_(FLDY) denote switches provided fordetecting the rotation of the detection gear 84 (see FIGS. 2 and 4). Theswitch SW_(FLSP) is arranged to produce an output which corresponds tothe output of the terminal 95 of the detection substrate 94 (see FIG. 5)and to supply the output to an input port FLSP of the microcomputer CPU.The switch SW_(FLDY) is arranged to produce an output which correspondsto the output of the terminal 97 and to supply the output to an inputport FLDY of the microcomputer CPU.

A symbol SW2 denotes a release switch. The release switch SW2 isarranged to be turned on by the second stroke of the pushing operationperformed on the shutter release button 2. The output of the switch SW2is supplied to an input port SW2 of the microcomputer CPU.

A symbol LED denotes a warning light emitting diode. The diode LED isdisposed either in the neighborhood of the view-finder field or on theoutside of the camera and is connected via a resistor R_(BC) to anoutput port LED of the microcomputer CPU. A symbol MD denotes a knowntransistor bridge circuit. The transistor bridge circuit MD is arrangedto control the motor M1 (see FIG. 2) in accordance with the instructionof the microcomputer CPU and is connected to output ports PM0 and PM1 ofthe microcomputer CPU. A symbol MG1 denotes a magnet for the leadingshutter blade group. The magnet MG1 is arranged to cause the leadingshutter blade group to begin to travel. A current supply is effected tothe magnet MG1 when a transistor TR_(MG1) is turned on through aresistor R_(MG1) by changing the output level of the output port PS0 ofthe microcomputer CPU to a high level. A symbol MG2 denotes a magnet forthe trailing shutter blade group. The magnet MG2 is arranged to causethe trailing shutter blade group to begin to travel when a currentsupply is effected to the magnet MG2. More specifically, the currentsupply to the magnet MG2 is effected when a transistor TR_(MG2) isturned on through a resistor R_(MG2) by changing the output level of theoutput port PS1 of the microcomputer CPU to a high level.

A reference symbol DATE denotes a known date imprinting device, which isarranged to imprint such data as a date, a day of the week, etc. on thefilm surface from the side of the back lid 70. The imprinting action isperformed when the level of an output port DT_(ON) of the microcomputerCPU becomes high. Further, in FIG. 11, a symbol GND denotes the ground.

The operation of the camera control circuit is as described below withreference to FIGS. 12(a), 12(b), 13(a) and 13(b) which are flow charts.

(Prewinding)

Step S1: Upon receipt of power from a power supply, the microcomputerCPU executes a program beginning with a start address START. Step S2:The output level of the output port V_(ON) of the microcomputer CPU ischanged to a high level (V_(ON) =1) to keep the transistor TR_(BAT) inan on-state for holding the power supply on. Step S3: The output of thefilm loading detection switch SWPT_(IN) is checked to see if the camerais loaded with the film. If so, the flow of operation proceeds to a stepS4. If not, the flow comes to a step S5. Step S4: The output of the backlid switch SWBP is checked to see if the back lid 70 is closed. If so,the flow comes to a step S7. If not, the flow comes to a step S50 whichis a release routine. Step S5: The back lid switch SWBP is checked inthe same manner as in the step S4. If the back lid 70 is found to beclosed, the flow proceeds to a step S6. If not, the flow comes to therelease routine of the step S50. Step S6: An EFPROM (a non-volatilememory) is disposed within the microcomputer CPU. One of the bits of theEFPROM is employed as an EFP flag. This flag is set at "1". Although itwill be described in further detail later on, the EFP flag is used formaking a decision when the back lid 70 is closed as to whether or notthe prewinding action is to be carried out. After the EFP flag is set at"1", the flow comes to the release routine of the step S50.

Step S7: If the EFP flag is at "1" (EFP=1), the flow proceeds to a stepS8. If it is found to be in its initial state (EFP=0), the flow comes tothe release routine of the step S50. Step S8: The voltage V_(BAT) of thebattery BAT is checked on the basis of the analog input obtained at theinput port AD_(IN3) (an AD conversion input). The voltage V_(BAT) isAD-converted by an AD converter which is disposed within themicrocomputer CPU. If the voltage V_(BAT) is found to be lower than apredetermined voltage level, the flow proceeds to a step S9 because ofthe probability of some faulty action. If the voltage is found to beabove the predetermined level and thus indicates no problem in terms ofpower supply, the flow proceeds to a step S10. Step 9: The output levelof the output port LED is changed to a high level to instruct thewarning light emitting diode LED to light up for indicating that thecamera cannot be operated due to the dropped state of the batteryvoltage V_(BAT). This instruction includes a function of causing thelight emitting diode LED to automatically extinguish its light bychanging the output level of the output port LED to a low level afterthe lapse of a given period of time. The flow then comes to a step S47which is a stop routine.

Step S47: All the sequences of processes ultimately come to this routinewithout fail. The level of the output port V_(ON) is set at a low level(V_(ON) =0). This causes the transistor TR_(BAT) to be turned off andrenders the regulator REG inoperative to turn off the power supply tothe circuit system. Further, there is a waiting period of time. Thepower supply Vcc is normally turned off while the microcomputer CPU isin the waiting state. The power supply Vcc sometimes still remains oneven when this waiting time has expired. Such occasions arise when thetransistor TR_(BAT) is kept on due to some reason other than for theoutput of the output port V_(ON). In other words, on such occasions, theone-shot circuit OS is operating with the power supply switch SW1 or theback lid switch SWBP is turned on. Under that condition, the flow comesback to the step S1 which is a start address for execution of a newsequence of processes.

Step S10: When the camera is loaded with a film, the back lid 70 isclosed, the flag EFP is at "1" and, further, the battery voltage V_(BAT)is at a level sufficiently high for operation, the camera performs theprewinding action in the following manner.

The motor M1 is caused to rotate in the normal direction (clockwise asviewed on FIG. 2) to drive the driving sprocket 58 and the spool 52. Theleader part of the film is first taken up onto the spool 52. After that,all the frame portions of the film are wound onto the spool 52 beforephotographing. The microcomputer CPU then controls the operation of themotor M1 as follows:

    ______________________________________                                                       PM0       PM1                                                  ______________________________________                                        Normal rotation: H (high)    L (low)                                          Reverse rotation:                                                                              L           H                                                Brake:           H           H                                                ______________________________________                                    

Further, a timer TMR is reset to its initial state (TMR=0). The timerTMR is provided for detection of any condition that does not permitcorrect film loading and a stretched condition of the film obtainedafter completion of prewinding all the frame portions of the film. Inthe event of these conditions, the film becomes immovable. Then, eitherof these two conditions can be considered to have occurred, if the filmis found to have not been moved to a predetermined amount within aperiod of time set at the timer TMR. Meanwhile, registers VR and VNRwhich are provided for battery voltage check are reset to their initialstates (VR=0 and VNR=0). Further, the register ECOUNT of the EFPROM(non-volatile memory) which is disposed within the microcomputer CPU isalso reset to its initial state (ECOUNT=0). The register ECOUNT isemployed as an electric film counter.

Step S11: The state of the back lid switch SWBP is checked to see if theback lid 70 is opened during the process of prewinding. If the back lid70 is found to have been opened, the flow proceeds to a step S12. Ifnot, the flow comes to a step S13. Step S12: With the back lid 70 openedduring the prewinding process, the rotation of the motor M1 is stoppedto bring the prewinding action to a stop and the flow comes to the stoproutine of the step S47. Further, if the back lid 70 is again closed,the flow of program proceeds from the start step S1 to carry out theprewinding action as the flag EFP then has not been reset and stillremains at "1". In this instance, however, any photographing operationon a film portion currently taken up by the prewinding action up to thetime of the release routine of a step S50 which will be described latercan be automatically inhibited as the register ECOUNT is reset to "0".

Step S13: The input port FLSP of the microcomputer CPU is checked to seeif the film has been moved by the prewinding action. If any change isfound in the signal supplied to the input port FLSP, the flow proceedsto a step S14. If not, the flow comes to a step 22. Step S14: With thefilm found to have moved through the change in the signal supplied tothe input port FLSP, the film stop detecting timer TMR is reset to itsinitial state (TMR=0). Step S15: The content of the register VR is addedto a value AD_(IN3) which is obtained by digital conversion of theanalog voltage of the battery voltage detecting input port AD_(IN3) bythe AD converter disposed within the microcomputer CPU. The result ofthis addition is again stored by the register VR(VR=VR+AD_(IN3)). Sincethe register VR has been reset to its initial state at the step S10, thevoltage value is incremented every time the signal supplied to the inputport FLSP changes and the result of addition is again stored at theregister VR. Further, the content of a register VNR is incremented by"1" (INC VNR). The number of times for which the voltage value is addedto register VR is thus shown by the register VNR.

Step S16: A check is made for the state of the input port FLDY. If theinput port FLDY is receiving a high level signal, i.e. if the brush 85is located in any area other than the brake control section and the dutycontrol section, the flow comes back to the step S11. If the signalsupplied to the input port FLDY is found to be at a low level, thusindicating that the brush 85 is within the brake control section or theduty control section, the flow proceeds to a step S17.

Further, in the time chart of FIG. 6, the time is assumed to be lapsingin the direction from the right to the left during the prewindingprocess.

Step S17: The level of the signal supplied to the input port FLSP of themicrocomputer CPU is checked for a discrimination between a high leveland a low level. If it is at a high level, the flow proceeds to a stepS18. If not, the flow comes to a step S19.

Referring again to the time chart of FIG. 6, a signal indicative of theprewinding process changes with the lapse of time, from the right-handside to the left-hand side. When, for example, this process reaches apoint on the right side of the brake control section, the flow proceedsin the order of the steps S13, S14, S15, S16, S17 and S19.

Step S18: When the brush 85 enters the duty control section from thebrake control section, the level of the signal supplied to the inputport FLSP changes from a low level to a high level. Under thiscondition, the content of the register ECOUNT which serves as anelectric film counter is incremented by one. After that, the flow comesback to the step S11. In other words, the number of the frame portionsof film is counted independently of the mechanical counter (the countergear 88) by incrementing the content of the register ECOUNT at a pointof time when the brush 85 shifts its position from the brake controlsection to the duty control section during the process of theprewinding.

Step S19: An average value V of voltage values obtained at the step S15is computed (V=VR/VNR). More specifically, the values of the powersupply voltage which has been obtained by computation (VR=VR+AD_(IN3))every time the signal supplied to the input port FLSP changes before thebrush 85 enters the brake control section are averaged. When the batteryvoltage V_(BAT) is found through this process to be no longer usable,the driving operation of the motor M1 is suspended at the ensuing step.Further, the averaging operation of the step S19 is performed for thepurpose of canceling any power supply noise that might occur during thedriving operation of the motor M1.

Step S20: A check is made to see if the voltage V obtained at the stepS19 is higher than a predetermined value M. If the voltage V is found tobe higher than the value M and is not giving any problem for theoperation of the camera, the flow comes back to the step S11. If thevoltage V is found lower than the value M and the battery BAT is thusconsidered to be not usable, the flow proceeds to a step 21. Further,the influence of the power supply noise is salient in the initial stageof the prewinding action. However, this presents no problem, because theflow is arranged to automatically come back to the step S11 if thecontent of the register VNR is not greater than a predetermined value.Step S21: The prewinding action is brought to a stop by stopping therotation of the motor M1. The warning light emitting diode LED isallowed to light up. After that, the flow proceeds to the stop routineIn this instance, if the power supply voltage is raised or if thebattery is replaced with a new battery, the prewinding action is resumedas the content of the EFPROM still retains in its stored state.

Step S22: With the signal supplied to the input port FLSP having beenfound to have no change at the step 13, the timer TMR is checked to seeif the counted value of the timer TMR has reached a predetermined valueK. If not, the flow comes back to the step 11 to repeat the routine ofthe steps S11, S13 and S22. Meanwhile, in a case where the above-statedsignal supplied to the port FLSP still remains unchanged even after thevalue of the timer TMR reaches the predetermined value K, the flowproceeds to a step S23. Step S23: With a discriminating value set at"3", when the value of the register ECOUNT which is employed as theelectric film counter is found to be greater than "3", thus indicating anormal state, the flow proceeds to a step S24. If the value is found tobe not greater than "3", film loading on the spool 52 is regarded as afailure. In that event, the flow comes to a step S12 to bring therotation of the motor M1 to a stop.

When the film is loaded on the spool 52 by the prewinding action, allthe frame portions of the film are taken up. The film then presentsitself in a stretched state. Under this condition, the flow proceedsfrom the step S22 to a routine of branching out to the step S23. Thefilm does not move also in the event of in apposite film loading whichprevents the film from being taken up onto the spool in the initialstage of the prewinding action. In that event, the flow also proceeds tothe routine of proceeding to the step S23 in the same manner as in thecase of the above-stated stretched state of film. At the step S23,therefore, a discrimination is made between the above-stated differentcases. More specifically, the film is considered to have becomeimmovable due to the stretched state if the content of the registerECOUNT is larger than "3" (a normal state), or due to the inappositefilm loading on the spool 52 if the content of the register ECONT is "3"or less (an abnormal state).

In a case where the rotation of the motor M1 comes to a stop with theflow coming to the step S12 due to the impossibility of film loading,the mechanical film counter enables the photographer to know theabnormal state and to try again to load the camera with the film.

Step S24: The flag EFP which is used as a flag for deciding whether ornot the prewinding action is to be performed again is reset (EFP=0).Therefore, in the ensuing sequence of processes, the flow branches fromthe step S7 to a step S50 and does not come to the above-stated routineof the prewinding action. Step S25: Since the prewinding action has beennormally carried out, the prewinding action is brought to a stop bystopping the motor M1. Step S26: The phase of the counter gear 88serving as the mechanical film counter and that of the register ECOUNTserving as the electric film counter are adjusted to each other bycarrying out an adding or subtracting operation at a shifting point ofthe brush 85 between the brake control section and the duty controlsection

In a case where the brush 85 has moved to a slight extent into the dutycontrol section after coming from the brake control section at the pointin time when the prewinding action comes to an end, the embodimentoperates as follows: In this instance, the counted values of themechanical and electrical film counters are normally incremented by oneat the above-stated shifting point, respectively. Sometimes, however,the tension of the film moves the film a little backward, i.e. towardthe film cartridge, to cause thereby the follower sprocket 80 to rotateto a small degree in the film rewinding direction when the drivingaction of the motor M1 comes to a stop (when a current supply to themotor is cut off). The brush 85 then might come back into the brakecontrol section As a result, the register ECOUNT serving as the electricfilm counter might fail to detect the backward movement while thecounter gear 88 serving as the mechanical counter is moved to an extentof one frame in the film rewinding direction (decremented by one). Inthat event, the counted values of these two counters come to differ byone from each other. If this count error is left uncorrected duringphotographing which is performed by rewinding the film, thephotographing operation would be performed including a portion of filmwhich has already been exposed to light during the prewinding action.

To solve this problem, therefore, steps S26 to S30 are provided foradjusting the value of the register ECOUNT to the counter gear 88 in thelast stage of the prewinding action.

Step S26: The signal supplied to the input port FLDY is checked for itslevel. If the signal level is found to be low, the flow proceeds to thestep S27. If it is high, the flow comes to a step 31. Step S27: Thesignal supplied to the input port FLSP is checked. If the level of thesignal is found to be high, the flow proceeds to the step S28. If it isfound to be low, the flow comes to the step S31. Step S28: A waitingtime is provided. The time is arranged to be sufficiently long forallowing the film to be moved back toward the film cartridge by the filmtension. Step S29: After the lapse of the waiting time of the step S28,the state of the signal supplied to the input port FLSP is againchecked. If the signal is still at a high level, the flow comes to thestep S31. If the signal is found to have changed to a low levelindicating thereby the occurrence of the above-stated phenomenon (thestate of having the mechanical counter rotated to a degree correspondingto one frame by the film tension). the flow proceeds to the step S30.Step S30: The value of the register ECOUNT serving as the electric filmcounter is decremented (or subtracted) by one to adjust it to the valueof the mechanical film counter.

Step S31: The motor M1 is caused to rotate in the reverse direction. Thereverse rotation (counterclockwise rotation as viewed on FIG. 2) of themotor M1 causes the planet gear 106 to mesh with the transmission gear120 of the mirror-driving and charge-driving system. This causes themirror driving gear 126 and the shutter charge gear 142 to rotate. Theclamp lever 170 is thus released from an initial position holding stateand is allowed to swing to the position of FIG. 7(c). Accordingly, theoutput of the motor M1 will be transmitted only to the film rewindingsystem when the motor M1 is rotated again in the normal direction. StepS32: The state of a signal supplied to the input port CMSP is checked.When the level of this signal changes from its initial low level to ahigh level, the flow proceeds to a step S33.

Step S33: When the level of the signal supplied to the input port CMSPchanges back to a low level with the motor M1 allowed to continuerotating in the reverse direction, the flow proceeds to a step S34. StepS34: The rotation of the motor M1 is temporarily brought to a stop. Thisstep is provided for finding if a blank charging process which takesplace according to the reverse rotation of the motor M1 at the precedingsteps S32 and S33 has come to an end. A phase obtained at the pointwhere the signal supplied to the input port CMSP changes from a lowlevel to a high level indicates the mirror-up action and thecancellation of the shutter charging action. Another phase obtained atthe point where this signal changes from a high level to a low levelindicates the mirror-up action and the shutter charging action.Therefore, when the flow comes to the step S34 through the steps S32 andS33, the blank charging process has been performed once.

Next, the motor M1 is again allowed to rotate in the normal direction.This time the output of the motor M1 is transmitted to the filmrewinding system as the change-over lever 170 has swung. In other words,the planet gear 106 meshes with the rewinding gear 110 to allow therewinding gear 110 to be driven by the motor M1.

Step S35: The content of a register PCOUNT is reset to its initial value(PCOUNT=0). Step S36: The state of the signal supplied to the input portFLSP is checked to find the position of the brush 85 in the initialstage of film rewinding. If the brush 85 is within the brake controlsection, the signal is at a low level and the flow comes to a step S40.If the brush is in any section other than the brake control section, thesignal is at a high level and then the flow proceeds to a step S37. StepS37: A check is made for the position of the brush 85 by checking alsothe state of the signal supplied to the input port FLDY. If the signalis found to be at a high level (indicating that the brush 85 is notwithin the brake and duty control sections), the flow comes to the stepS40. If the signal is found to be at a low level (indicating that thebrush 85 is within the duty control section in conjunction with theresult of the check made at the step S36). the flow proceeds to a stepS38. Step S38: Since the brush 85 has been determined to be within theduty control section in the initial stage of film rewinding, the countedvalue of the register ECOUNT which serves as an electric counter isdecremented by one. Further, in the time chart of FIG. 6, the lapse oftime is assumed to progress from the left to the right in the case offilm rewinding.

Step S39: The flow waits until the level of the signal supplied to theinput port FLDY becomes high thus indicating that the brush 85 is in anysection other than the duty and brake control sections After that, theflow proceeds to the step S40.

Step S40: The input port FLSP is checked. If any change occurs in thesignal supplied to the input port FLSP, the flow proceeds to a step S41.If not, the flow comes to a step S42. Step S41: The value of theregister PCOUNT is incremented by one and the flow comes back to thestep S40. Step S42: The input port FLDY is checked. If the signalsupplied to the input port FLDY is found to be at a high level, the flowcomes back to the step S40. If the signal is found to be at a low level,the flow proceeds to a step S43. The steps S40 to S42 are provided forthe purpose of storing information on the number of signals which areobtained from the comb-shaped pattern 94a shown in FIG. 5 and which aresupplied to the input port FLSP while the signal level of the input portFLDY remains high.

Step S43: The value of the register PCOUNT is compared with apredetermined value M. If the value is found to be smaller than thepredetermined value M, the flow comes back to the step S35. If the valueis found to be not smaller than the predetermined value M, the flowproceeds to a step S44.

In the case of the routine of this embodiment, the film is rewound tosome extent upon completion of the prewinding action for the purpose ofphase-adjusting the exposing frame portion of film to the rotatingposition of the follower sprocket 80 (i.e. the rotating position of thebrush 85). However, if the rewinding amount is too small, a film cuttingposition might come within an exposed (photographed) frame in cuttingthe film off from the film cartridge during a film developing process.The step S43 is, therefore, provided for rewinding the film to asufficient extent to avoid occurrence of such a problem. Morespecifically, the film rewinding extent from an initial state to a pointwhere the brush 85 comes to the duty control section is judged from thenumber of teeth of the comb-shaped pattern 94a which have actually comeinto sliding contact with the brush 85. In a case where this number issmaller than the predetermined value M, the film rewinding amount isconsidered to be too small. In that event, actual photographing is notallowed until the film is further rewound to the extent of anotherframe.

Step S44: The motor M1 is duty-controlled before the brake controlsection for the purpose of making constant the overrun which takes placebefore the motor M1 actually comes to a stop after commencement of brakecontrol. The method for the duty control over the motor M1 is well knownand therefore requires no detailed description. Briefly stated, however,this control is performed for brake application to the motor M1 bysupplying a current to the motor in an alternating pulse-like mannerinstead of effecting a full current supply to the motor to lower theeffective voltage.

Step S45: The duty control is performed over the motor M1 while thebrush 85 is moving within the duty control section. When it is foundthrough the change to a low level of the signal supplied to the inputport FLSP that the brush 85 has entered the brake control section, theflow proceeds to a step S46. Step S46: Braking control is applied to themotor M1. Then, the value of the register ECOUNT is decremented by one("1" is subtracted).

The camera is completely readied by the above-stated routine forphotographing. The flow, therefore, comes to the stop routine.

(Photographing)

Step S50: This is a release routine after the prewinding controlprocess. Step S51: A digital value AD_(IN1) which has obtained by AD(analog-to-digital) converting, at the microcomputer CPU, an analogsignal supplied from the output terminal BV1_(OUT) of the photometriccomputing circuit MET is stored by the register BV1 (BV1=AD_(IN1)) Thisis a value "BV-AV" in terms of the APEX system. A digital value ADIN2which has been obtained also by AD converting a film sensitivity valueis stored by a register SV (SV=AD_(IN2)). The value AD_(IN2) is a value"SV" in terms of the APEX system. Further, a shutter speed value isobtained from the data stored by the above-stated registers BV1 and SV(TV=BV1+SV). The shutter speed value thus obtained is stored by aregister TV. The content of the register TV is a value "TV" in the APEXsystem.

Step S52: A check is made for the state of the release switch SW2 whichis arranged to be turned on by the second stroke of a pushing operationon the shutter release button 2. The flow proceeds to a step S53 onlywhen the switch SW2 is turned on. Step S53: Similar to the case of thestep S8, the voltage V_(BAT) of the battery BAT is checked. If thebattery voltage is found to be a predetermined value or less, the flowproceeds to a step S54. If it is greater than the predetermined value,the flow comes to a step S55. Step S54: The output level of the outputport LED is made to be high to light up the warning light emitting diodeLED. This indicates that the camera is unable to operate due to the dropof the battery voltage. Step S55: The motor M1 is rotated in the reversedirection to perform the mirror-up action and the cancellation of theshutter charging action.

Step S56: The motor M1 is rotated in the reverse direction until a highlevel signal is supplied to the input port CMSP before the flow proceedsto a next step S57. The mirror driving gear 126 and the shutter charginggear 142 are driven. The movable mirror 134 is raised to be retractedfrom the optical path for an exposure. The shutter charging state of thecamera is canceled to render the shutter operable. Step S57: The brakecontrol is performed to bring the rotation of the motor 1 to a stop.Step S58: The APEX value TV is converted into an actual shutter speed(expansion to an actual time value). Step S59: The output level of theoutput port DT_(ON) is made to be high to cause the date imprintingdevice DATE to begin to imprint data on the film surface.

The date imprinting device DATE is arranged in a known manner and doesnot require detailed description. Briefly stated, however, the deviceDATE is arranged as follows For example, a plurality of LCD segmentswhich are shaped into the Chinese character " " are laterally aligned onthe back lid side in a position confronting the film surface. The lighttransmitting parts of these segments are selected to form figures andcharacters indicative of a date, time, etc. by exposing the film surfaceto a transmission light thus obtained.

A timer DTMR which is provided for counting an imprinting period of timeis started. The content of the timer DTMR depends on the content of theregister SV. However, since the value SV of the content of the registerSV is in the APEX system, the value of the content of the timer DTMR isa value "α×2.sup.β-SV " (wherein α and β are constants) which isobtained by converting the APEX value SV into an actual time value.

Further, the timer interruption of the timer DTMR is allowed to takeplace at the step S59 (EN I). After expiration of the time of the timerDTMR, an interruption is allowed independently of the program of themain routine. By the interrupt routine, an imprinting action isaccomplished by executing the following processes:

DT_(ON) =0: The output port DT_(ON) is changed to a low level.

DTMR.STOP: The timer DTMR is stopped.

RTN: The flow comes back to the main routine.

Step S60: The output level of the output port PS0 is changed to a highlevel to effect a current supply to the magnet MG1 for causing theleading group of shutter blades to begin to travel. The leading group ofshutter blades then travels and an exposure begins Further, the actualtime of the shutter speed value obtained at the step S58 is actuallycounted. The time value thus obtained is used as exposure time. Uponcompletion of the actual time counting action, the output level of theoutput port PS1 is changed to a high level to effect thereby a currentsupply to the magnet MG2 for causing the trailing group of shutterblades to begin to travel. The trailing group of shutter blades thentravels to bring the exposure to a stop.

Step S61: The flow waits for a period of time required for the travel ofthe trailing group of shutter blades. Step S62: The output levels of thetwo output ports PS0 and PS1 are changed to low levels to bring thecurrent supply to the magnet MG1 and MG2 to a stop. Step S63: The motorM1 is rotated in the reverse direction to lower the mirror and chargethe shutter.

Step S64: The motor M1 is rotated in the reverse direction until a lowlevel signal is obtained at the input port CMSP. After that, the flowproceeds to a step S65. Meanwhile, with the motor M1 rotated in thereverse direction, the mirror driving gear 126 and the shutter chargegear 142 are driven once again. As a result, the movable mirror 134 islowered (to permit sighting at the view finder), and the shutter ischarged. Step S65: The brake control is performed to bring the motor M1to a stop. Further, even if the output of the output port DT_(ON) is ata high level (thus indicating that the time of the timer DTMR has notbeen expired), the date imprinting action is brought to an end byforcedly changing the output level of the output port DT_(ON) to a lowlevel (DT_(ON) =0). The reason for this is as follows: In the event ofan extremely low degree of film sensitivity, the imprinting action mightnot be completed within the charging period of time. However, in themeantime, film rewinding would be performed at a next step forphotographing on a next frame. If, despite of this, the date imprintingaction is allowed to continue, the imprint of figures and characterswould be flown. Should the imprinting action still continue even aftercompletion of the charging action at the step S65, therefore, theimprinting action is forcedly stopped to prevent thereby the imprintedfigures and characters from being flown. Further, the interruption isdisabled and any interruption is inhibited thereafter (DIS I).

Step S67: After waiting for a standard period of time required forrewinding one frame portion of film, the flow comes to the stop routine.This step is provided for the following reason: If the camera isarranged to perform no film rewinding action when the camera is notloaded with a roll of film, a frame transport speed obtained when theuser tries a continuous shooting operation on the camera at a camerashop would be too fast as compared with a speed obtainable for actualphotographing to be performed with the camera loaded with the film. Thiswould mislead the user about the specifications of the camera. This,however, can be prevented by the step S67.

Step S68: The motor M1 is rotated in the normal direction to rewind thefilm for photographing on a next frame. Step S69: Before proceeding to astep S70, the flow waits until the level of the signal supplied to theinput port FLDY becomes high because: Since the motor M1 begins torotate in the normal direction while the brush 85 is at a phase withinthe brake control section, the flow is arranged to wait until the brush85 moves away from that phase. Step S70: Before proceeding to a stepS71, the flow waits until the signal level obtained at the input portFLDY becomes low. In other words, the flow waits until the brush 85enters the duty control section. Step S71: The duty control is performedover the motor M1. Step S72: Before proceeding to a step S73, the flowwaits until the level of the signal supplied to the input port FLSPbecomes high. In other words, the flow waits until the brush 85 entersthe brake control section.

Step S73: Since the brush 85 has entered the brake control section, oneis subtracted from the value of register ECOUNT which serves as anelectric film counter (DEC ECOUNT). Step S74: If the value of theregister ECOUNT resulting from the subtraction is not "2", the flowproceeds to a step S75. If the value is "2", the flow comes to a stepS76. In other words, when the value of the register ECOUNT is "2", theflow proceeds to a different routine for controlling the termination ofphotographing. In this instance, the counter gear 88 which serves as amechanical film counter shows "0" when the value of the register ECOUNTis "2". In other words, a film frame number indicator 88c shows "0"through a display window 89 provided in the camera body. Further, at thebeginning of the prewinding action, a mark "E" on the film frame numberindicator 88c of the counter gear 88 is located in a positioncorresponding to the display window 89. The photographable area of thefilm is arranged to begin at a point located at a distance of threeframes from this mark "E". Since the register ECOUNT is arranged to beat its value "0" when this mark "E" is obtained. The photographable filmarea (frames) comes to an end when the value of the register ECOUNT is"3" (ECOUNT=3).

Step S75: Since the value of the register ECOUNT is not "2", the filmstill has photographable frame portions. Therefore, the brake is appliedto the motor M1 to bring the film rewinding action to a stop. Afterthat, the flow proceeds to the stop routine to wait for photographing ona next frame. The end of photographing is normally determined by thisroutine.

Step S76: Since the value of the register ECOUNT is "2", photographingcan be regarded as completed for all the photographable frames.Therefore, the motor M1 is allowed to continue rotating in the normaldirection to control the film being taken up into the film cartridge.Step S77: The timer TMR for detecting the stop of the film is reset toits initial value (TMR=0).

Steps S78 and S79: When the film ceases to move, the flow proceeds to anext step S80 like in the cases of the steps S13 and S22 described inthe foregoing. In the case of the steps S78 and S79, the stop of thefilm movement means that the film has completely been taken up into thefilm cartridge. Step S80: The film rewinding action is stopped by brakeapplication to the motor M1. Step S81: The motor M1 is rotated in thereverse direction for blank charging. Steps S82 and S83: Like n the caseof the steps S32 and S33 described in the foregoing, the motor M1 isallowed to continue rotating in the reverse direction until the mirrordriving gear 126 and the shutter charge gear 142 make one turnrespectively. This blank charging process is performed mainly forenabling the change-over lever 170 to swing back to its initial positionby setting free the planet gear 106 which has been caused to mesh withthe rewinding gear 110 by the film rewinding action, as shown in FIG.10(d).

Step S84: The blank charging action is brought to an end by brakeapplication to the motor M1. The flag EFP which is used for decidingwhether the prewinding action is to be carried out or not is set at "1"(EFP=1). By this, the camera is readied for the prewinding action to beperformed when the camera is loaded with a roll of film next time.Further, the register ECOUNT which serves as an electric film counter isreset to its initial state (ECOUNT=0). After this, the flow comes to thestop routine of the step S47 and the control action comes to an end.

Next, the operation of the camera is further described as follows withimportance attached to the operation of the mechanical arrangementthereof:

(Prewinding Action)

This embodiment is arranged to perform prior to photographing, theprewinding action by which all the frame portions of the frame portionsof film are wound up beforehand, and then the film is rewound one by oneat every shooting. When the back lid 70 is closed with a film cartridgeloaded, the microcomputer CPU detects that fact through the back lidswitch SWBP and causes the motor M1 to rotate clockwise (in the normaldirection). The rotation of the motor M1 in the normal direction causesthe planet gear 28 included in the transmission system on the side ofthe lower output shaft of the motor M1 to revolve. The planet gear 28thus comes to mesh with the transmission gear 32 as shown in FIG. 10(a).This causes through the transmission gears 34 and 36 the sun gear 38 torotate clockwise.

The rotation of the sun gear 38 in turn causes the first planet gear 40to revolve. The gear 40 comes to mesh with the spool drivingtransmission gear 48. Meanwhile, the second planet gear 46 also revolvesto come to mesh with the sprocket driving transmission gear 54 as shownin FIG. 3(a). That causes both the spool 52 and the driving sprocket 58to rotate in the film winding direction. As a result, the leader part ofthe film F is first moved toward the spool 52 by the driving sprocket58. Then, with the spool claws 52a coming to mesh with the perforationof the film F, the film is taken up onto the spool 52. Further, theplanet gear 106 included in the transmission system on the side of theupper output shaft of the motor M1 tries to revolve in a direction inwhich it meshes with the rewind gear 110. However, under this condition,the movement of the planet gear 106 is prevented by the firstrestrictive projection 170b and is merely allowed to idly rotate, asshown in FIG. 9(a). With the leader part of the film F coming to betaken up onto the spool 52, the difference in the peripheral speed ratiobetween the transmission system on the side of the spool 52 and thetransmission system on the side of the driving sprocket 58 causes therotational frequency of the second planet gear 46 which is rotated bythe drive of the motor M1 and that of the transmission gear 54 which isrotated by the driving sprocket 58 following the movement of the film tono longer coincide with each other. This causes the second planet lever44 to jump clockwise (see FIG. 3(a)). The clockwise jumping of thesecond planet lever 44 causes the click part 44c to override the clickprojection 62b of the holding lever 62. As a result, the second planetgear 46 is kept in a state in which it does not mesh with theabove-stated transmission gear 54, as shown in FIG. 3(b). After this,the film is wound by the drive of the spool 52 alone. This methodenables the film F to be automatically loaded without fail, because: Ifthe film is simply wound by the spool 52 alone from the beginning, theleader part of the film cannot be reliably transported to the spool 52.Whereas, the arrangement to have the film F driven by the drivingsprocket 58 until the leader part of the film is wound onto the spool 52ensures highly reliable automatic film loading. This is a greatadvantage.

After the film leader part is thus wound onto the spool 52, the drivingsprocket 58 is no longer required to be driven and, therefore, thedriving action is then automatically switched over to the spool 52 only.This arrangement of the embodiment is, therefore, highly advantageous interms of efficient film winding. The peripheral speed ratio differencebetween the spool 52 and the driving sprocket 58 is preferably set insuch a way as to ensure that the above-stated holding action on thesecond planet lever 44 is performed immediately after the film leaderpart is completely taken up onto the spool 52.

After this, the film winding action continues until all the frameportions of the film are wound up. This film winding action is arrangedto be confirmable by the photographer through the intermittent advancingrotation of the counter gear 88 which is performed according to thedriven rotation of the follower sprocket 80. As mentioned in theforegoing, the counter gear 88 is provided with a film frame numberindicator 88c. The indicator 88c is arranged in combination with adisplay window 89 which is provided on the camera body as shown by atwo-dot chain line in FIG. 2. The arrangement, therefore, enables thephotographer to know that the film F is wound up by seeing changestaking place in a figure appearing in the window 89.

When the film F stretches after all the frame portions are taken up, thedetection gear 84 which is associated with the follower sprocket 80stops rotating. As a result, a film movement indicating signal which hasbeen continuously supplied from the detection substrate 94 to themicrocomputer CPU (see FIG. 6) ceases to be produced. This informs themicrocomputer CPU of the end of film winding, and the rotation of themotor M1 is brought to a stop.

Following this, the motor M1 is caused to rotate counterclockwise (inthe reverse direction). The rotation of the motor M1 in the reversedirection causes the planet gear 28 of the film winding system torevolve in a direction in which it moves away from the transmission gear32. Meanwhile, the planet gear 106 which belongs to the transmissionsystem on the side of the upper output shaft of the motor M1 is causedto revolve and come to mesh with the transmission gear 120 of themirror-driving and shutter-charging driving system. This causes themirror driving gear 126 and the shutter charge gear 142 to make onerotation. The movable mirror 134 is driven to change its state from theinitial lowered state to its raised state and to the lowered state byone turn of the mirror driving gear 126. The shutter charge lever 146 isdriven to change its state from its charging state to its chargecanceling state and then to the charging state by one turn of theshutter charge gear 142. Then, a blank charging action is performeduntil a ground level signal is produced from the detection pattern 162which is provided as a next shutter charge completion phase on thesignal substrate 160 (see FIG. 8).

The blank charging action which is performed by the reverse rotation ofthe motor M1 relieves the change-over lever 170 from the state in whichit is held in its initial position by the clamp lever 174 and allows thelever 170 to swing clockwise to shift its position to the positions oneafter another shown in FIGS. 7(a), 7(b) and 7(c). As a result, the firstrestrictive projection 170b comes away from its interposed position inbetween the planet gear 106 and the rewinding gear 110 as shown in FIG.9(b). Meanwhile, the second restrictive projection part 170c comes inbetween the planet gear 28 and the transmission gear 32, as shown inFIG. 10(b). After that, therefore, the planet gear 106 and the rewindinggear 110 can mesh with each other when the motor M1 rotates in thenormal direction. On the other hand, the rotation of the motor M1 in thenormal direction does not allow the planet gear 28 to mesh with thetransmission gear 32.

Next, the motor M1 is allowed to rotate in the normal direction, for thefollowing reason: In order to ensure that the rewinding action to beperformed thereafter on each frame portion of the film is accuratelyaccomplished, the film must be rewound back to a dividing (or indexing)position. A figure of the film frame number indicator 88c of the countergear 88 appearing under the condition thus obtained indicates a numberof photographable frames.

The prewinding action is completed by the above-stated process. Thecamera remains in this condition until a shutter release operation isperformed.

(Photographing Operation)

When the release switch SW2 is turned on with a pushing operationperformed on the shutter release button 2 (see FIG. 1), themicrocomputer CPU detects that fact and causes the motor M1 to rotate inthe reverse direction. This causes the mirror driving gear 126 and theshutter charge gear 142 to rotate. The movable mirror 134 is raised andthe shutter charge lever 146 acts to cancel the charge (see FIG. 7(b)).Then, the rotation of the motor M1 in the reverse direction is broughtto a stop. The shutter is allowed to operate under this condition. Uponcompletion of the travel of the trailing group of shutter blades, themotor M1 is caused to further rotate in the reverse direction. Again themirror driving gear 126 and the shutter charge gear 142 are rotated.This time, the movable mirror 134 is lowered and the shutter chargelever 146 is caused to perform its charging action as shown in FIG.7(c). Upon completion of these actions, the motor M1 is brought to astop. The motor M1 is then immediately controlled to rotate in thenormal direction. The planet gear 106 of the transmission system on theside of the upper output shaft of the motor M1 then revolves to meshwith the rewind gear 110 to rewind the film. Further, when the motor M1rotates in the normal direction, the planet gear 28 which belongs to thetransmission system on the side of the lower output shaft of the motorM1 also revolves to try to mesh with the transmission gear 32. However,in this instance, the change-over lever 170 has moved clockwise to havethe second restrictive projection 170c inserted in between the planetgear 28 and the transmission gear 32, as shown in FIG. 10(b). Therefore,the two gears 28 and 32 do not mesh with each other and the output ofthe motor M1 is not transmitted to the film winding transmission system.

When the film rewinding action is performed, the follower sprocket 80rotates clockwise following the movement of the film (see FIG. 2). Thedetection gear 84 also rotates in synchronism with this. A little beforethe film F is rewound to an extent corresponding to one frame, the motorM1 is decelerated by a duty control driving action. When the film F isrewound exactly to the extent of one frame portion thereof, the motor M1is brought to a stop by brake application control.

This brings the camera into a state of waiting for photographing on anext frame. The counter gear 88 rotates clockwise to a degree of onepitch to have its frame number display decremented by one.

After that, the actions mentioned above are repeated to carry out aphotographing operation every time the shutter release button SW2 ispushed.

(Film being taken up into Cartridge)

Upon completion of the photographing operation, the electric filmcounter is checked to find whether the film frame number currentlyobtained is the second frame. If so, the motor M1 is controlled torotate in the normal direction to have the film taken up into the filmcartridge. The term "electric film counter" as used here means thecounter (register ECOUNT) disposed in the microcomputer CPU. Theelectric counter is arranged to count up every time one frame portion ofthe film is taken up during the prewinding action and to count downevery time one frame portion of the film is rewound. Further, theelectric counter is used as a source of information for inhibitingphotographing on a number of frame portions (three frame portions in thecase of this embodiment) which have been exposed to light following theleader part of film at the beginning of the prewinding action and whichcorrespond to a number of frame portions to be wound up in the initialstage of the ordinary conventional automatic film loading process. Therotation of the motor M1 is stopped upon detection that the followersprocket 80 ceases to rotate either when the film F is completely takenup into the film cartridge or immediately before that.

Following this, a blank charging action is performed by causing themotor M1 to rotate in the reverse direction to cause the mirror drivinggear 126 and the shutter charge gear 142 to rotate. The rotation of themotor M1 in the reverse direction is stopped when these gears make oneturn (to come to the mirror-down phase passing through the mirror-upphase). The blank charging action is performed after the film has beentaken up into the cartridge for the purpose of causing the planet gear106 which has meshed with the rewind gear 110 by the above-stated filmwinding action to revolve and move toward the transmission gear 120; andalso for causing the planet gear 28 to move by revolution away from thetransmission gear 32. In other words, the blanking action is performedfor the purpose of ensuring that the ensuing prewinding action isaccurately performed with these gears 28 and 106 appropriatelypositioned for allowing the change-over lever 170 to swing(counterclockwise) back into its initial position when the back lid 70is opened for replacing the film with a new film.

Since the planet gear 106 is revolved to shift its position toward thetransmission gear 120 by the above-stated blank charging action, thereset lever 178 is caused to swing counterclockwise by the spring 180when the back lid 70 is closed, as shown in FIG. 9(d). Then, the pushingprojection 178b comes to push the upper end of the change-over lever 170to cause the lever 170 to move counterclockwise (as the spring 180 isarranged to have a stronger spring force than that of the spring 172which is exerting a clockwise urging force on the lever 170). Thecounterclockwise movement of the change-over lever 170 causes the clamplever 174 to move with its pin 174c guided by the guide projection 170e.The latch claw 174a then comes to engage the clamp projection 170d. Thechange-over lever 170 thus comes back and locked in its initialposition, as shown in FIGS. 2, 7(a), etc. Therefore, the firstrestrictive projection 170b which is disposed at the upper end part ofthe change-over lever 170 comes in between the planet gear 106 and therewind gear 110 to inhibit them from meshing with each other when themotor M1 rotates in the normal direction. Meanwhile, the secondrestrictive projection 170c of the lever 170 stays away from itsposition between the planet gear 28 and the transmission gear 32 toallow them to come to mesh with each other when the motor M1 rotates inthe normal direction.

When the back lid 70 is again closed after replacement of the film F,the reset lever 178 is pushed to swing clockwise by the pushingprojection 70d of the back lid 70. This relieves the change-over lever170 from a pushed state. However, since the change-over lever 170 islocked by the clamp projection 170d of the clamp lever 174 as mentionedabove, the lever 170 continues to stay in its held position.

Further, when the back lid 70 is opened, the reset lever 60 in the filmwinding system is relieved from a state in which it is pushed by thepushing projection part 70b. Then, the reset spring 66 pushes the resetlever 60 to swing clockwise. Therefore, the holding lever 62 also swingsclockwise as shown in FIG. 3(c). The pin 62a of the holding lever 62then pushes the projection 44b of the second planetary lever 44 to causethe lever 44 to swing clockwise. This brings the second planet gear 46back to its initial position where the gear 46 can mesh with thetransmission gear 54. When the back lid 70 is again closed after this,no change occurs in the position of the second planetary lever 44 whilethere simply obtains the state of FIG. 3(a).

Further, with the back lid 70 closed, the counter reset lever 90 isrelieved from its state of being pushed by the pushing projection 70cand is allowed to swing counterclockwise by the spring 92. Accordingly,the pushing part 90c of the counter reset lever 90 pushes the counteradvancing shaft 86 in the direction opposite to the counter gear 88.This sets the counter gear 88 free to allow it to be moved clockwise bythe force of a spring which is not shown back to a position where theinitial position mark "E" becomes visible through the display window 89.The frame number indication is thus reset to its initial state. However,in the case of an ordinary photographing operation, the counter gear 88has already been intermittently brought back to the above-stated initialposition when the film is to be taken up into the film cartridge aftercompletion of photographing on all the frame portions of the film.Therefore, the above-stated returning action which is performed by meansof the above-stated spring is not required except in cases where theback lid 70 is opened during the process of, for example, ademonstrative photographing operation on the camera without loading itwith any film.

In the case of the film winding driving mechanism of the embodimentdescribed, the first planetary lever 42 and the second planetary lever44 which are separately disposed, one in the transmission system on theside of the spool 52 and the other in the transmission system on theside of the driving sprocket 58, are arranged to have the sun gear 38 incommon. This arrangement enables the embodiment to adequately cope withsuch a situation that the back lid 70 is opened under the film rewindingcondition before completion of photographing for all the frame portionsof the film and is then the back lid 70 is again closed to allow thefilm to be rewound. In other words, with the back lid 70 opened, thesecond planetary lever 44 is unlocked and becomes swingable to bringabout a condition under which the second planet gear 46 is allowed tomesh with the transmission gear 54. Therefore, in rewinding the film,the planet gears 40 and 46 both come to rotate following the rotation ofthe spool 52 and that of the driving sprocket 58 caused by filmrewinding (in the direction reverse to film winding rotation). Then,although the spool 52 and the driving sprocket 58 differ in peripheralspeed ratio, i.e. the peripheral speed ratio of the spool 52 is larger,the arrangement to provide the planetary clutch mechanism also in thetransmission system on the side of the spool 52 like in the case of thisembodiment enables the first planetary lever 42 to swing to adequatelydisengage the planet gear 40 from the transmission gear 48.

As apparent from the flow charts of FIGS. 12(a) and 12(b), all the frameportions of film can be wound onto the spool 52 by the prewindingaction. Upon completion of the prewinding action, there obtains astretched state of the film. As a result, the signal which has beengenerated by the movement of the film perforation stops to be generatedany longer. Therefore, at the step S22, the flow branches out to a stepS23. However, in the event of a failure in the automatic film loadingdue the to incorrect film loading on the spool 52 at the beginning ofthe prewinding action, the flow likewise branches out from the step S22to S23 as the film also does not move. The step S23 is, therefore,provided for making a discrimination between the two conceivable causesfor the immovable state of the film including the automatic film loadingfailure and the completion of the prewinding action. In other words, atthe step S23, the register ECOUNT serving as the electric film counteris checked for the result of electric film counting action thereof. Ifthe value of the register ECOUNT is greater than the predetermined value"3" thus indicating that four or more frame portions of film havealready been wound by the prewinding action, the film is determined tohave been completely taken up by the prewinding action. If the value ofthe register ECOUNT is found to be not greater than the predeterminedvalue "3", it means that the amount of film wound up is three or lessframe portions, thus indicating that the prewinding action has notcompletely been performed. In that case, the automatic film loadingaction onto the spool 52 is determined to have failed.

The predetermined value "3" is selected for the discriminating process,because: taking a safety margin into consideration, an amount of filmwhich is likely to be exposed to light during the process of pulling theleader part of the film out of the film cartridge in loading the filmonto the spool (a non-photographable amount of film) normally does notexceed three frame portions of the film. In the event of a roll of filmwhich is cut to a short length including, for example, only five frameportions, it is only one or two frame portions that are actually usablefor photographing. Even in such a case, the above-stated arrangementenables the embodiment to accurately make a discrimination between thefailure of the automatic film loading and the completion of theprewinding action.

Further, since the prewinding action is to be continuously accomplisheduntil all the frame portions of film are wound up, the embodiment isarranged to make a battery voltage check prior to the prewinding actionand to allow this action to be carried out only when the power supplyvoltage is found to be at a predetermined level or above.

Further, the power supply voltage check is also arranged to be madeafter the start and during the process of the prewinding action. Then,if the voltage level is found to have dropped to a level below thepredetermined level, the prewinding action is stopped and held inabeyance. The prewinding action is allowed to be resumed when the powersupply voltage is again raised to the predetermined level or above byreplacing the battery or the like, so that the film can be saved frombeing wasted.

Further, another advantage of the embodiment is as follows: In a casewhere the back lid of the camera is inadvertently opened during theprocess of the prewinding action, the prewinding action can be resumedwhen the back lid is again closed. Therefore, a photographable portionof film which still remains within the film cartridge when the back lidis inadvertently opened can be saved from being wasted.

What is claimed is:
 1. A motor-driven camera of the prewind type inwhich, when loading a film, an automatic loading for automaticallywinding the film onto a take-up spool is performed, then a prewindingaction for preliminary winding the film is consecutively performed and,after completion of the prewinding action, one frame of the film isrewound for every photographing shot, comprising:(a) an electric filmcounter for counting the number of frames of the film in response to thetransport of the film; (b) detection means for detecting the movement ofthe film; and (c) a determining circuit for determining a state of thecamera when said detection means has detected that the film is notmoving, (c-1) said determining circuit determining the prewinding actionto have been completed when a counted value of said electric filmcounter is greater than a predetermined value, and (c-2) saiddetermining circuit determining the automatic loading to have failedwhen the counted value of said electric film counter is not greater thansaid predetermined value.
 2. A camera according to claim 1, furthercomprising: a rewind circuit for rewinding the film to a small extentprior to photographing shot when said determining circuit has determinedthe prewinding action to have been completed.
 3. A camera according toclaim 1, further comprising: a stop circuit for stopping the transportof the film when said determining circuit has determined the automaticloading to have failed.
 4. A camera according to claim 2, furthercomprising: a stop circuit for stopping the transport of the film whensaid determining circuit has determined the automatic loading to havefailed.
 5. A camera according to claim 1, further comprising: one-frametransport detecting means for detecting the transport of every one frameof the film; and a rewind circuit for rewinding the film to a smallextent prior to photographing shot to adjust the phase of said one-frametransport detecting means when said determining circuit has determinedthe prewinding action to have been completed.
 6. A camera according toclaim 1, further comprising: a motor driving circuit for causing theautomatic loading to start in response to closing of a back lid of thecamera; a voltage detecting circuit for detecting a voltage of a powersupply in response to closing of the back lid; and a control circuit forprohibiting an operation of said motor driving circuit to cause theautomatic loading not to start when said voltage detecting circuit hasdetected that said voltage of the power supply is lower than apredetermined level.
 7. A camera according to claim 1, furthercomprising: back lid detecting means for detecting opening and closingof a back lid of the camera; and a prewinding control circuit forcontrolling the prewinding action to be suspended or to be resumed, saidcontrol circuit causing the prewinding action to be suspended whenopening of said back lid is detected by said back lid detecting meansduring the prewinding action and, after that, to be resumed when closingof said back lid is detected by said back lid detecting means.
 8. Acamera according to claim 1, further comprising: back lid detectingmeans for detecting opening and closing of a back lid of the camera; anda voltage detecting circuit for detecting a voltage of a power supplyduring the prewinding action; and a prewinding control circuit forcontrolling the prewinding action to be suspended or to be resumedaccording to the voltage detected by said voltage detecting circuit,said control circuit causing the prewinding action to be suspended whensaid voltage detecting circuit has detected that said voltage of thepower supply is lower than a predetermined level and, after that, to beresumed when said voltage detecting circuit has detected that saidvoltage of the power supply is not lower than said predetermined level.9. A camera according to claim 1, further comprising: a mechanical filmcounter for indicating the number of transported frames of the film,said mechanical film counter indicating the number of frames by using arotary indicating plate.
 10. A camera according to claim 9, wherein saidelectric film counter and said mechanical film counter are both arrangedto perform counting actions by using a common member arranged to rotateaccording to the transport of the film.
 11. A motor-driven camera of theprewind type in which, when loading a film, a leader part of the film iswound onto a take-up spool, a plurality of frames of the film areconsecutively wound by a film winding action immediately following saidleader part and, after that, one frame of the film is rewound for everyphotographing shot, comprising:(a) an electric film counter for countingthe number of frames of the film according to the transport of the film;(b) detection means for detecting the movement of the film; and (c) acircuit for prohibiting a photographing operation when said detectionmeans has detected that the film is not moving, said circuit beingarranged to prohibit the photographing operation when a counted value ofsaid electric film counter is not greater than a predetermined value.12. A camera according to claim 11, wherein said circuit is arranged topermit the photographing operation when the counted value of saidelectric film counter is greater than said predetermined value.
 13. Acamera according to claim 12, further comprising: one-frame transportdetecting means for detecting the transport of every one frame of thefilm; and a rewind circuit for rewinding the film to a small extentprior to photographing shot to adjust the phase of said one-frametransport detecting means when the counted value of said electric filmcounter is greater than said predetermined value.
 14. A camera accordingto claim 11, further comprising: a voltage detecting circuit detecting avoltage of a power supply in response to closing of a back lid of thecamera; and a control circuit for prohibiting an action of winding theleader part of the film onto the take-up spool when said voltagedetecting circuit has detected that said voltage of the power supply islower than a predetermined level.
 15. A camera according to claim 11,further comprising: back lid detecting means for detecting opening andclosing of a back lid of the camera; and a control circuit forcontrolling the film winding action to be suspended and to be resumed,said control circuit causing the film winding action to be suspendedwhen said back lid detecting means has detected opening of said back lidduring the film winding action and, after that, to be resumed when saidback lid detecting means has detected closing of said back lid.
 16. Acamera according to claim 11, further comprising: back lid detectingmeans for detecting opening and closing of a back lid of the camera; avoltage detecting circuit for detecting a voltage of a power supplyduring the film winding action; and a control circuit for controllingthe film winding action to be suspended and to be resumed during thefilm winding action according to the voltage detected by said voltagedetecting circuit, said control circuit causing the film winding actionto be suspended when said voltage detecting circuit has detected thatsaid voltage of the power supply is lower than a predetermined leveland, after that, to be resumed when said voltage detecting circuit hasdetected that said voltage of the power supply is not lower than saidpredetermined level.
 17. A camera according to claim 11, furthercomprising: a mechanical film counter for indicating the number oftransported frames of the film, said mechanical film counter indicatingthe number of frames by using a rotary indicating plate.
 18. A cameraaccording to claim 17, wherein said electric film counter and saidmechanical film counter are both arranged to perform counting actions byusing a common member arranged to rotate according to the transport ofthe film.
 19. A camera according to claim 5, wherein said one-frametransport detecting means detects the transport of every one frame onthe basis of a signal generated in response to a movement of the film.20. A camera according to claim 7, wherein said back lid detecting meansincludes a switch which changes over an output signal thereof inresponse to a movement of the film.
 21. A camera according to claim 8,wherein said back lid detecting means includes a switch which changesover an output signal thereof in response to a movement of the film. 22.A camera according to claim 11, wherein said detection means detects amovement of the film on the basis of a signal generated in response tothe movement of the film.
 23. A camera according to claim 13, whereinsaid one-frame transport detecting means detects the transport of everyone frame on the basis of a signal in response to a movement of thefilm.
 24. A camera according to claim 15, wherein said back liddetecting means includes a switch which changes over an output signalthereof in response to a movement of the film.
 25. A camera according toclaim 16, wherein said back lid detecting means includes a switch whichchanges over an output signal thereof in response to a movement of thefilm.